Lewinsky is to be interrogated by Republican prosecutors from the U.S. House of Representatives about her relationship with Clinton. The president's lawyers will also be present as well as some senators. It will be the first time the Clinton attorneys will have a chance to talk with Lewinsky.

The 100 Senators sitting as Clinton's jury are to review a videotape of the session and decide later whether to release the material or to call Lewinsky as a witness in the trial in full public view.

The prosecutors are trying to gather evidence that Clinton attempted to cover up his affair with Lewinsky through illegal means. The House impeached Clinton in December on charges of perjury and obstruction of justice. If convicted by a two-thirds vote by the Senate, the president would be removed from office.

Political observers say Clinton is not likely to be convicted, barring some new and damaging revelations. The Senate has 55 Republicans and 45 Democrats; 67 votes are needed to convict. Balloting is expected largely along party lines.

Clinton has acknowledged having had an affair with Lewinsky but has denied of committing any impeachable offenses. The president, a Democrat, contends the impeachment charges were pressed against him by his political enemies.

Meanwhile, The New York Times reported Sunday in a front-page article that special prosecutor Kenneth Starr is considering bringing regular criminal charges against Clinton before the president's term expires in January, 2001.

The Times said that Starr, the independent counsel appointed to investigate Clinton, believes he enjoys the constitutional authority to seek a grand-jury indictment of Clinton. The newspaper, quoting Starr associates who asked not to be identified, said he has not decided yet whether to bring charges in a criminal court.

Starr declined comment on the report.

Many constitutional experts believe that an incumbent president cannot be indicted and put on trial in a criminal court. They say only the House of Representatives can level charges against a sitting president through a bill of impeachment and that only the Senate can convict him.

Senator Joseph Lieberman, a Democrat from Connecticut, noted there has been no Supreme Court decision on whether a sitting president can be indicted. It is only the second time in the history of the Republic that a president faces a Senate trial. No president has ever been convicted by the Senate.

Lieberman added: "It seems to me that the strong possibility of an indictment of the president either in the office or out reminds us that he will be subject to the rule of law regardless of what the Senate does."

Senator Richard Shelby, a Republican from Alabama, said it was possible that less than 50 senators would vote to convict Clinton. Senator John Breaux, a Louisiana Democrat, predicted a dozen Republicans would join the Democrats in voting down the articles of impeachment. Balloting is expected on February 12.

The House prosecutors will also question White House aide Sidney Blumenthal on Tuesday and Clinton confidant Vernon Jordan on Wednesday.

Clinton spent the weekend at the Camp David presidential retreat in Maryland. Aides said he planned to watch on television on Sunday the Super Bowl, a championship American football game between the Atlanta Falcons and the Denver Broncos.